GFP expression of the transgenic fish in adult Schwann cells. Immunofluorescence staining of adult PNS was performed with a monoclonal antibody to GFP. Adult trunks of wild type (A-C) and transgenic GFP fish (D-F) were sliced horizontally (10 μm). The pictures show bright-field (A, D), fluorescence (B, E), and merged images (C, F). Myelin structures were observed between muscles (white arrow head). Bars: 20 μm.